MOD 7 Flashcards
What are infectious diseases?
Are diseases that are caused by a pathogen entering the body and can be transferred from person to person.
What are non-infectious diseases?
Diseases that can cannot be spread from person to person
What is the cause of infectious diseases? (2)
Bacteria
Pathogens
What causes non infectious diseases?(2)
Genetics
Environment factors
What was the past theory of infectious diseases?
Spontaneous generation, which is living organism (fles) could arise from the decay of susbtances (rotten food)
What is the theory now of infectious diseases?
The germ theory of disease, it states that diseases and decay are the product of living organisms,
What Are communicable diseases?
Disease that is transmitted from plant to plant or animal to animal.
What are viruses(3) ?
-Package of DNA/RNA surrounded by proteins
-Extremely small
-Non cellular and therefore non living and can’t grow or reproduce
-Invades host cells -> injects its genetic material into host cell -> cell
-metabolises new viruses
-Can only survive in live cells
-Vaccines are effective in getting rid of viruses
What is bacteria?(3)
-Tiny prokaryotic single cellular
-Non nucleus
-Have cell wall and membrane
-Single strand of DNA
-Reproduce via binary fission
-Invade cells and form colonies and disrupt normal cell function
Can survive in reservoirs
What are fungi?
-can be multicellular or unicellular
-Eukaryotic
-Reproduce asexually via spores
-Has membrane and cell walls
What is protozoa?
-Single celled eukaryotic organisms
-Have cell membrane
-NO cell wall
-Heterotrophs
-Form colonies that disrupt normal cell function
What are Heterotrophs?
Absorbs nutrients from their host
What is Epidemic:?
sudden spike in the prevalence of an infectious disease in a region / community
What is Pandemic?
sudden spike in a disease across the entire world
What is Enzootic?
endemic amongst animals in a particular region
What is the cycle of disease transmission? (6)
1- infectious agent
2- reservoir
3- portal of exit ( respiratory, gastrointestinal, genitourinal, skin)
4- mode of transmission (direct contact, indirect contact, vector transmission)
5- portal of entry
6- susceptible host
What are infectious agents in the cycle, what arethey capable of?
They are pathogens, which are capable of infectious and causing disease, the more virulent a pathogen is, the greater effect it will have on the health of the host.
What is virulent?
The ability of pathogen infecting a host, more virulent more harm
What is a reservoir?
Is where the pathogen normally lives and reproduces
- soil
- water
- faeces
What is the portal of entry and exits of the infectious agent? (4)
- respiratory- includes the mouth and throat, increase mucus production and can exit by coughing and enter vi breathing close to an infected individual
- gastrointestinal- includes the stomach and intestines (both), oral cavity rectum is the portal of exit through diarrhoea and vomiting
- genitourinal- includes the reproductive organs, can be exited via urethra and through sexual contact
- skin- it provides a barrier, when infected the blood can exit the wound and cause transmission and diseases can enter the wound and go into the bloodstream
What is transmission?
Is the way a pathogen spreads diseases from one host to the next
What is direct contact, 2 examples?
Where there is physical contact, between the host and non infected person or reservoir and a infected person
- contact of body fluids with infected person
- touching the person infected
What is indirect contact,2 examples?
When the host and another organism have no direct contact with each other, requires an intermediate between the host as the next, this can be contaminated material,
Contaminated food
Contaminated surgical equipment
What is vector transmission, 2 examples?
It occurs through a transmission agent, such as mosquitoes and flies, where they bite and transmit the disease
- mosquitoes (malaria)
- hendra virus (fruit bats
What is a susceptible host in the cycle?
Organism that will be infected, which depends on genetics, immunity and overall health
What is the cause of ebola, is it RNA or DNA?
Server infectious diseases caused by ebola virus, it’s an single stranded RNA virus
How can ebola be transmitted (3)?
- bodily fluids such as blood from infected person
- contaminated surfaces
- sexual contact
What are the symptoms of ebola(3)?
- Flu like symptoms
- diarrhoea
- internal bleeding
How to manage(as soon as it happens) the outbreak of ebola(3)?
Quarantine
Lockdown
Social distancing
How to control the future outbreaks of ebola(1)?
Vaccines
What are some risk factors (catching) of ebola (2)?
Working in the medical industry —> Exposure to infected objects
Travelling to area with recent outbreaks
What are the steps of making a petri dish?(7)
1- sterilise the bench using alcohol
2- using an inoculating loop put into flames across motion s to sterilise
3- dip the inoculating loop into sample
4- open the petri dish at a 45 degree angle so that the bacteria in the air doesn’t go inside
5-using the inoculating loop in a snake like movement place into the pert dish
6- put upside down so condensation happens and doesn’t go into the sample
7- leave for about 2-3 days in the incubator at 35 de
What is koch’s postulate experiment ?
His experiment involved to take the blood sample of a infected person and then isolated and culture the disease in a petri dish/ agar plate then he would insert it into a healthy person, and observed the symptoms
What was the conclusion of Koch’s postulate experiment?
He concluded that when giving the disease of the infected individual the healthy individual will develop the same symptoms as the infected.
What disease does the koch use for this postulate experiment?
He examined anthrax which had a rod shaped bacteria, used sheeps as a subject.
What were teh2 breakthroughs of Koch’s postulates experiment?
1- discovery of mycobacterium tuberculosis, which cause tuberculosis
2- discovery of a bacterium causes cholera
What was the criteria of koch postulate experiment? (3)
- same organism
- pure culture is injected into healthy host (same symptoms must be presented)
- micro organism must be isolated from the second and third host before injected (same symptoms must be presented)
What are the procedure of
Koch postulates?
1-specific microbe must be present in every host with the disease
2-The specific microorganism must be isolated from the host and grown in a pure culture, on a sterilised agar plate
3-A potential host when inoculated with sample of the Pure culture must develop the same symptoms as the original host
4- The specific microbe must be isolated from the second host and cultured and identified as the same species as originally cultured.
What is pasteurisation?
Heating kills most microbes responsible for spoiling the product
How do we conduct the pasteur’s experiment?(5)
1 - pour in bone broth into 2 conical flasks
2- place swan necks on them both
3- using hot pate we heat the conical flask to sterilise them
4- take one of the swan neck off
5- observe
Why do we use a swan neck?
It allows air to enter but it stops microbes and dirt from entering as they get suck in the
S- shape.
What did Pasteur observe from his broth experiments?
That the broth in the open necked flask became cloudy, indicates there are germs, but the broth in the swan neck was unchanged free of germs.
His experiment demonstrated that microbial germs are airbones, and life cannot be sterilised mediums.
What is the relationship between pasteur and anthrax?
Pasteur investigated the cause of anthrax while Koch’s finding showed that animals were contracting disease if they had been in contact with an infected individual.
How can animals still get infected if not in contact with animals?
animals were contracting disease even if they had no contact as they were grazing on soil which had the disease of the buried infected animals.
What are some symptoms of diseases in plants?(2)
Stunt growth
chlorosis(yellowing on leaf, lacks chlorophyll)
What does innate mean?
Inherited and non specific, part of the first line and second line of defence
What are biotrophs?
This is where a pathogen enters a plant host but doesnt kill, as they depend on tht plant for nutrients
What are necrotrophs?
They plant through the excretions of toxic chemicals which cause cell death.
What do fungal pathogens do in plants?
They inhibits the function of the stomat and.inhibit cellular processes such as photosynthesis, which leads to chlorosis
How do viral pathogens move in plants?
Via plasmodesmata, apoplast (through cell wall), symplast(through cytoplasm)
What does adaptive mean?
Developed over time, specific and is part of the 3rd line of defence
What are the physical lines of defence?(5)
1.skin(epithelial tissue)- acts as a barrier, as has blood vessels to provide early access to WBC and also has keratin.
2.Tight junctions- the blood vessels and the endothelial cells(lining of teh BV) are tightly together to prevent the entry of pathogens as it restricts the diffusion of microbes.
3.Mucus- which trap foreign pathogens, and also contain iron containing enzymes which help to deal with pathogens ,
4.Increase urination- to help flush out pathogen
5.Diarrhoea and vomiting- helps to flush out pathogens
What is a certivic plug?
Contain mucus which guards the uterus protect against pathogen entry during pregnancy
What do mucous membranes assist in the physical defence?(2)
they found in mouth, they act as a cell junction between epithelial cells to anchor them more efficiently and restricting pathogen entry, they also contain cilia which beat to remove particles from respiratory system
What is keratin?
Is a waterproof protein that provides an extra layer of security against pathogen entry, as it is mechanically tough.
It is secreted by the skin cells
What Are the Chemical lines of defence(5)?
1.Urine - have (Anti microbal peptides) AMPs scresed by cell lining of the urinary tract to prevent bacteria form binding on epithelial cells, and AMPs cause cell lyse in bacterial cells, unine has wide pH under basics conditions phagocytic cells work best.
2.Sebum and sweat- to waterproof and lubricate(minimise friction) the skin, lysozymes are severed and it breaks down bacterial cell walls
3.Saliva- it contain antimicrobial substance like lysozymes and immunoglobulin A
4.Tears- it contain antimicrobial substances
5.Gastric secretions- has HCL which has a ph around 1-2 which discourages the growth and survival of microbes
What are 3 physical barriers in plants?
-Thick cuticle to withstand enzyme secretion
-Vertical hanging leaves, so water doesn’t accumulate to reduce likelihood of pathogen reservoirs forming
-Smaller stomata to limit the pathogen from entering
What are 2 chemical barriers in plants?
-Plants produce enzymes that break down pathogen derived toxins
-Chemical receptors to detect the presence of a pathogen, the raptors detect for PAMP which is secreted by the pathogen,
What are the 2 plant defences?
Passive→ physical and chemical defences
Active→pathogenesis recognised and what happens next
What are the 2 active defences?
-Delayed active response
-Rapid active response
What are the rapid active responses?–Plants(3)
-Decrease the permeability of the plant cell membrane
-Plant releases H2O2 (hydrogen peroxide) which can kill microbes directly
-Apoptosis (programed cell death) happens to cell around the pathogen so the pathogens nutrient supply dies so does the pathogen
What is the delayed active response of the plant?(3)
-Repair the wound in the bark so that further pathogen don’t enter
-lysozyme -like- chemical which have antimicrobial actions
-Salicylic acid plays a role in memorising a particular pathogen, this is called systemic acquired resistance
What does the second line of defence consist of?
Nonspecific phagocytes and use the lymphatic system
What does the lymphatic system consist of?
- lymph nodes
- lymph vessels
- tissue fluid (lymph)
What is the role of the lymph nodes?
It filters out the pathogens inside the lymph fluid when it makes its way into the lymph nodes, and once it is filtered the waste leaves via perspiration and urine.
How can we pinpoint the site of infection using lymph nodes?
By the size of the nodes the change in size and texture, helps to pinpoint the site as drainage routes are known.
What are the different white blood cells?(7)
1.Mast Cells - opens up blood vessels so that WBC can go into tissues, and it releases histamine and prostaglandins to induce inflammation and call phagocytic cells
2.Macrophages - phagocytic cells comes from blood vessels
3.Natural killer cells- kills tumours cells and virus infected cells
4.Dendritic cells- triggers the 3rd line of defence as it presents the antigen to helper t cells
5.Monocytes- are able to differentiate into macrophages and dendritic cells
6.Neutrophil- are the first responders and is a phagocytic cell and can recruit immune cells o the site
7.Basophil- against parasites and releases histamine that causes inflammation.
What is granuloma?
These are dead cells which surround the infected cell and prevents the spread of infection
What is wound healing?
Where there is a breach in body barriers and are exposed to pathogens and then use platelets through blood vessels contract (vasoconstriction), then a protein fibrin forms a mesh to trap more platelets to form a clot to seal the wound, then the inflammatory response begins.
What is inflammation?
It is a non specific defence and is active when histamines and prostaglandins are released(mast and basophil cells), cause the capillaries o diallate increase blood flow to site of infection, and increases the permeability of blood vessels, which allows certain WBC to move through
Increase the temp so that kill the bacteria and the WBC can work at its optimal temp
What do eosinophils do?
Destroy macroparasites, through releasing enzymes into the parasite
What do basophils do?
Produce histamine for inflammatory response
What are 2 lymphocytes?
T and B Cells
What are phagocytes?
Work by engulfing and destroying pathogens
What are the 4 types of T cells?
Cytotoxic(killer) T cells
Memory T cells
Helper T Cells
Suppressor T cells
Where are B cells matured in?
Bone marrow
Where are T cells matured in?
Thymus gland
What are the 2 B cells?
Plasma cells
Memory B cells
What are 2 types of adaptive immunity?
Humoral immunity - uses antibodies to fight pathogens outside cells in fluid
Cell mediated immunity- to fight pathogens inside cells
What happens when the antigen comes on its second exposure(secondary response)?
1.The antigen stimulates the memory T and memory B cells
2.Memory B and T cells clones into antibodies and killer T cells
3.Some remain incase pathogen comes again
What are the steps of the 3rd line of defence?
1.Dendritic cells present the antigen by holding the antigen on the MHCII marker
2.Moves to the lymph nodes to give to the Helper T Cells by the t cell receptor
3.The Helper T cells release TL-2 which turns immature B cells into mature B cells
4.Then the mature B cells turn into plasma and memory B cells
5.Then the plasma B cells make antibodies which attack pathogen outside cells
3) TL-2 changes the immature T cells to mature T cells
4) The the mature T cells become memory T cells and Cytotoxic T cells which go and attack pathogens inside cells
What is the second way the body can react on the first exposure?
1.Pathogen makes contact with immature T and B cells in the lymph node or spleen
2.Immature B and T cells carry the antigen on the MCHII marker to helper T cells
3.Which release TL-2
4.Then matures B and T cells
What are antibodies?
They are proteins produced by the body in response to the presence of specific antigens and produced by plasma cells
What do suppressor T cells do?
Responsible for stopping the adaptive response when the infection has been defeated, bu inactivating the B cells and the cytotoxic T cells
What do memory T and B cells do?
Give long term immunity and destroys antigenic cell before symptoms appears
What is the purpose of MHCI marker?
On infected cells which represents the fragment of antigen
How do cytotoxic T cells work?
The Killer T cell binds to the MCHI marker with the infected cell, and it releases perforin, which makes holes on the target cell, making water enter rapidly and then it lyse(bursts)
What are the different ways the antigen may be destroyed after the formation of the antibody- antigen complex? (4)
1.Neutralisation- antibody binds to the block parts antigen needs or survival
2.Agglutination- antibodies bind to more than one epitope causing them to clump together and destroyed by phagocytosis
3.Precipitation- soluble antigens can be precipitated and destroys the activity then broken down by phagocytosis
4.Destruction by complement- antibodies can stock to surface of bacterial cells and lyse happens
How do antibodies work?
It binds to the antigen (epitope), and then forms a antibody -antigen complex which then immobilises the antigen
Which marker plays a role in recognizing oneself?
MHCI marker, but it is hard to find 2 people with the same MHC marker so they give immunosuppressive drugs which makes the recipient more susceptible to infections
What are the steps of allergic reaction?
1.B cell encounters allergen and the differentiate into plasma cells
2.Plasma cells produce antibodies
3.Antibodies bind to specific receptors on the surface of mast cells
4.Then they release histamine which causes the allergic reactions.
What is an Allergic reaction?
When the immune system overreacts to a wrong substance.
What can cause the disease transmission?(4)
Directly transfer from host to host
Lack of education regarding an epidemic
Poverty
Small gene pool—> genetic diversity
What are some measure to prevent the spread of infectious disease? (4)
- Personal and community hygiene
-Quarantine
-Education—> public health campaigns
-antibiotics
What is Quarantine?
The isolation of infected organism to stop the spread of a disease
What is a vaccination?
Is the process of making people resistant to infection, they are prepared from weakened or dead pathogens to provoke the immune system , to produce killer T cells and Antibodies
What is herd Immunity?
When unvaccinated individual are protected because the reservoir of pathogen are low, and is less likely to come in contact with infected individual
What are mRNA vaccines?
Weakened or dead pathogens injected into our body to teach our body how to make proteins that will trigger an immune response,
What is the process of mRNA vaccine in covid?
1- mRNA is injected to produce a spike protein (harmless piece)and then the mRNA is broken down and removed
2- the cells display the spike protein on the surface using the MHCI marker, so that the immune system can recognize it doesn’t belong, and produce antibodies and immune cells to fight it off.
3- now the body has learnt how to protect itself from infections—> without the risk of potential symptoms.
What are pesticides?
Chemicals used to kill pests of plants, including pathogens and vectors, to control the diseases.
What are the adv of mRNA vaccines?(2)
Designed to treat different virus variants
Inexpensive
What are 2 public health campaigns?
-Government regulations→ sterilising equipment, cooking and correct garbage disposal
-Public education
What are the dis of mRNA vaccines?
Need booster shots
What are fungicides used in?
Killing fungal pathogens
What are insecticides used in?
Kill insects
What are Herbicides?
Killing weeds
What is DDT?
It is an insecticide to control Typhus, by killing lice transmission, by pathogen, however the effectiveness was reduced due to insects being resistant due to natural selection.
What is the problem with pesticides?
The build up of resistance, which reduces the effectiveness of pesticides and require stronger pesticides.
What are antibiotics?
Used to treat bacterial infections by killing or slowing the growth of the bacteria.
How does natural selection happen in antibiotics resistance?
So there is a small no. of people with resistant bacteria, then selection pressure occurs, killing the unfavourable trait, the reproduction of the resistance to bacteria(favourable trait), then there is a change in population in resistant bacteria.
What are antivirals?
Used to treat viral infections, by slowing down the progress,
What are the 3 steps of antivirals?
-Before cell entry- virus ability to bind to surface proteins
-During Viral synthesis- inhibiting reverse transcription
-Release phase- blocking virus ability to be released from host cell
What are 2 examples of aboriginal medications?
Smoke bush
Kakadu plum
What is the smoke bush used for?
The use was for treatment of AIDS/HIV, as there is a molecule present for killing the HIV virus
What is Kakadu plum used for?
It has high levels of vitamin C, as it has a sour taste due to high acid conc. They used to help treat scurvy diseases.
why might octane undergo incomplete combustion
Being a long carbon chain may undergo incomplete combustion2C8H18+ 24O2→14CO2+ 2CO + 2C + 18H2O
what are some adaptations for Protozoan
Some protozoans enter a new host through a vector
what are some adaptations for virus
mutate to change the shape of the antigens so that the immune system does not recognise them
what are some adaptations for bacteria
biofilm to provide protection against the host’s immune response
